SEMICONDUCTOR LASER DEVICE, DIFFRACTION GRATING STRUCTURE, AND DIFFRACTION GRATING
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| Titel: | SEMICONDUCTOR LASER DEVICE, DIFFRACTION GRATING STRUCTURE, AND DIFFRACTION GRATING |
|---|---|
| Document Number: | 20180351328 |
| Publikationsdatum: | December 6, 2018 |
| Appl. No: | 16/058356 |
| Application Filed: | August 08, 2018 |
| Abstract: | A semiconductor laser device is a vernier-type wavelength-tunable semiconductor laser device including an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods. At least one of the first and second reflective elements has a sampled grating structure having a reflection comb spectrum in which reflection phases at the respective reflection peaks are aligned and the intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than the intensity of a reflection peak within the laser emission wavelength bandwidth. |
| Assignees: | FURUKAWA ELECTRIC CO., LTD. (Tokyo, JP) |
| Claim: | 1. A vernier-type wavelength-tunable semiconductor laser device comprising an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods, wherein at least one of the first and second reflective elements has a sampled grating structure having a reflection comb spectrum in which reflection phases at the respective reflection peaks are aligned and an intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than an intensity of a reflection peak within the laser emission wavelength bandwidth. |
| Claim: | 2. The semiconductor laser device according to claim 1, wherein at least one of the first and second reflective elements has a light-emitting region. |
| Claim: | 3. A vernier-type wavelength-tunable semiconductor laser device comprising an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods, wherein at least one of the first and second reflective elements is a diffraction grating having a sampled grating structure including a plurality of diffraction grating structures, each of the diffraction grating structure having a structure that is substantially centrosymmetric in a light progressing direction, and has the sampled grating structure having a reflection comb spectrum in which an intensity of a reflection peak outside a set laser emission wavelength bandwidth is lower than an intensity of a reflection peak within the laser emission wavelength bandwidth. |
| Claim: | 4. The semiconductor laser device according to claim 3, wherein at least one of the first and second reflective elements has a light-emitting region. |
| Claim: | 5. A vernier-type wavelength-tunable semiconductor laser device comprising an optical resonator, constituted by first and second reflective elements having reflection comb spectra in which reflection peaks are arranged on a wavelength axis in a substantially periodic manner and having mutually different periods, wherein at least one of the first and second reflective elements is a diffraction grating of a sampled grating structure including a plurality of diffraction grating structures, a plurality of sets of a high-refractive-index portion and a low-refractive-index portion having a lower refractive index than the high-refractive-index portion are alternately arranged in a predetermined direction in the diffraction grating structure, when a structure in which a plurality of sets of the high-refractive-index portion and the low-refractive-index portion are arranged in an alternately periodic manner is set as a basic structure, the diffraction grating structure has a structure formed by omitting at least one of the high-refractive-index portions from the basic structure, omitting at least one of the low-refractive-index portions, omitting at least one boundary between the high-refractive-index portion and the low-refractive-index portion, or performing a combination thereof, and the diffraction grating structure has a structure including a plurality of portions with alternating arrangement of the high-refractive-index portion and the low-refractive-index portion phase shifted by a ½ period from the basic structure. |
| Claim: | 6. The semiconductor laser device according to claim 5, wherein at least one of the first and second reflective elements has a light-emitting region. |
| Claim: | 7. The semiconductor laser device according to claim 5, wherein the diffraction grating structure has a structure approximately providing a shape obtained by Fourier formation of a desired reflectivity spectrum. |
| Claim: | 8. The semiconductor laser device according to claim 5, wherein the diffraction grating structure has a structure approximately providing a sinc function shape obtained by Fourier formation of a rectangular window function. |
| Claim: | 9. The semiconductor laser device according to claim 8, wherein the diffraction grating structure has a structure that is substantially centrosymmetric in the predetermined direction. |
| Claim: | 10. A semiconductor laser device comprising: a first reflection film; a second reflection film having a higher reflectivity than the first reflection film; an active layer arranged between the first reflection film and the second reflection film; and a diffraction grating provided along the active layer in vicinity of the active layer and having a diffraction grating structure, wherein a plurality of sets of a high-refractive-index portion and a low-refractive-index portion having a lower refractive index than the high-refractive-index portion are alternately arranged in a predetermined direction in the diffraction grating structure, when a structure in which a plurality of sets of the high-refractive-index portion and the low-refractive-index portion are arranged in an alternately periodic manner is set as a basic structure, the diffraction grating structure has a structure formed by omitting at least one of the high-refractive-index portions from the basic structure, omitting at least one of the low-refractive-index portions, omitting at least one boundary between the high-refractive-index portion and the low-refractive-index portion, or performing a combination thereof, and the diffraction grating structure has a structure including a plurality of portions with alternating arrangement of the high-refractive-index portion and the low-refractive-index portion phase shifted by a ½ period from the basic structure, and laser emission is performed in a plurality of longitudinal modes. |
| Claim: | 11. The semiconductor laser device according to claim 10, wherein the diffraction grating structure has a structure approximately providing a shape obtained by Fourier formation of a desired reflectivity spectrum. |
| Claim: | 12. The semiconductor laser device according to claim 10, wherein the diffraction grating structure has a structure approximately providing a sinc function shape obtained by Fourier formation of a rectangular window function. |
| Claim: | 13. The semiconductor laser device according to claim 12, wherein the diffraction grating structure has a structure that is substantially centrosymmetric in the predetermined direction. |
| Claim: | 14. The semiconductor laser device according to claim 10, wherein the diffraction grating is a diffraction grating having a sampled grating structure including a plurality of the diffraction grating structures. |
| Claim: | 15. A diffraction grating structure obtained by alternately arranging a plurality of sets of a high-refractive-index portion and a low-refractive-index portion having a lower refractive index than the high-refractive-index portion in a predetermined direction, wherein when a structure in which a plurality of sets of the high-refractive-index portion and the low-refractive-index portion are arranged in an alternately periodic manner is set as the basic structure, the diffraction grating structure has a structure, formed by omitting at least one of the high-refractive-index portions from a basic structure, omitting at least one of the low-refractive-index portions, omitting at least one boundary between the high-refractive-index portion and the low-refractive-index portion, or performing a combination thereof, and the diffraction grating structure has a structure including a plurality of portions with alternating arrangement of the high-refractive-index portion and the low-refractive-index portion phase shifted by a ½ period from the basic structure. |
| Claim: | 16. The diffraction grating structure according to claim 15, wherein the diffraction grating structure has a structure approximately providing a shape obtained by Fourier formation of a desired reflectivity spectrum. |
| Claim: | 17. The diffraction grating structure according to claim 15, wherein the diffraction grating structure has a structure approximately providing a sinc function shape obtained by Fourier formation of a rectangular window function. |
| Claim: | 18. The diffraction grating structure according to claim 17, wherein the diffraction grating structure has a structure that is substantially centrosymmetric in the predetermined direction. |
| Claim: | 19. A diffraction grating of a sampled grating structure, the diffraction grating comprising the diffraction grating structures according to claim 15. |
| Current International Class: | 01; 01; 01 |
| Dokumentencode: | edspap.20180351328 |
| Datenbank: | USPTO Patent Applications |
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